1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Local endpoint object management 3 * 4 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/net.h> 12 #include <linux/skbuff.h> 13 #include <linux/slab.h> 14 #include <linux/udp.h> 15 #include <linux/ip.h> 16 #include <linux/hashtable.h> 17 #include <net/sock.h> 18 #include <net/udp.h> 19 #include <net/af_rxrpc.h> 20 #include "ar-internal.h" 21 22 static void rxrpc_local_processor(struct work_struct *); 23 static void rxrpc_local_rcu(struct rcu_head *); 24 25 /* 26 * Compare a local to an address. Return -ve, 0 or +ve to indicate less than, 27 * same or greater than. 28 * 29 * We explicitly don't compare the RxRPC service ID as we want to reject 30 * conflicting uses by differing services. Further, we don't want to share 31 * addresses with different options (IPv6), so we don't compare those bits 32 * either. 33 */ 34 static long rxrpc_local_cmp_key(const struct rxrpc_local *local, 35 const struct sockaddr_rxrpc *srx) 36 { 37 long diff; 38 39 diff = ((local->srx.transport_type - srx->transport_type) ?: 40 (local->srx.transport_len - srx->transport_len) ?: 41 (local->srx.transport.family - srx->transport.family)); 42 if (diff != 0) 43 return diff; 44 45 switch (srx->transport.family) { 46 case AF_INET: 47 /* If the choice of UDP port is left up to the transport, then 48 * the endpoint record doesn't match. 49 */ 50 return ((u16 __force)local->srx.transport.sin.sin_port - 51 (u16 __force)srx->transport.sin.sin_port) ?: 52 memcmp(&local->srx.transport.sin.sin_addr, 53 &srx->transport.sin.sin_addr, 54 sizeof(struct in_addr)); 55 #ifdef CONFIG_AF_RXRPC_IPV6 56 case AF_INET6: 57 /* If the choice of UDP6 port is left up to the transport, then 58 * the endpoint record doesn't match. 59 */ 60 return ((u16 __force)local->srx.transport.sin6.sin6_port - 61 (u16 __force)srx->transport.sin6.sin6_port) ?: 62 memcmp(&local->srx.transport.sin6.sin6_addr, 63 &srx->transport.sin6.sin6_addr, 64 sizeof(struct in6_addr)); 65 #endif 66 default: 67 BUG(); 68 } 69 } 70 71 /* 72 * Allocate a new local endpoint. 73 */ 74 static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, 75 const struct sockaddr_rxrpc *srx) 76 { 77 struct rxrpc_local *local; 78 79 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); 80 if (local) { 81 atomic_set(&local->usage, 1); 82 atomic_set(&local->active_users, 1); 83 local->rxnet = rxnet; 84 INIT_LIST_HEAD(&local->link); 85 INIT_WORK(&local->processor, rxrpc_local_processor); 86 init_rwsem(&local->defrag_sem); 87 skb_queue_head_init(&local->reject_queue); 88 skb_queue_head_init(&local->event_queue); 89 local->client_conns = RB_ROOT; 90 spin_lock_init(&local->client_conns_lock); 91 spin_lock_init(&local->lock); 92 rwlock_init(&local->services_lock); 93 local->debug_id = atomic_inc_return(&rxrpc_debug_id); 94 memcpy(&local->srx, srx, sizeof(*srx)); 95 local->srx.srx_service = 0; 96 trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL); 97 } 98 99 _leave(" = %p", local); 100 return local; 101 } 102 103 /* 104 * create the local socket 105 * - must be called with rxrpc_local_mutex locked 106 */ 107 static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net) 108 { 109 struct sock *usk; 110 int ret; 111 112 _enter("%p{%d,%d}", 113 local, local->srx.transport_type, local->srx.transport.family); 114 115 /* create a socket to represent the local endpoint */ 116 ret = sock_create_kern(net, local->srx.transport.family, 117 local->srx.transport_type, 0, &local->socket); 118 if (ret < 0) { 119 _leave(" = %d [socket]", ret); 120 return ret; 121 } 122 123 /* set the socket up */ 124 usk = local->socket->sk; 125 inet_sk(usk)->mc_loop = 0; 126 127 /* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */ 128 inet_inc_convert_csum(usk); 129 130 rcu_assign_sk_user_data(usk, local); 131 132 udp_sk(usk)->encap_type = UDP_ENCAP_RXRPC; 133 udp_sk(usk)->encap_rcv = rxrpc_input_packet; 134 udp_sk(usk)->encap_destroy = NULL; 135 udp_sk(usk)->gro_receive = NULL; 136 udp_sk(usk)->gro_complete = NULL; 137 138 udp_encap_enable(); 139 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6) 140 if (local->srx.transport.family == AF_INET6) 141 udpv6_encap_enable(); 142 #endif 143 usk->sk_error_report = rxrpc_error_report; 144 145 /* if a local address was supplied then bind it */ 146 if (local->srx.transport_len > sizeof(sa_family_t)) { 147 _debug("bind"); 148 ret = kernel_bind(local->socket, 149 (struct sockaddr *)&local->srx.transport, 150 local->srx.transport_len); 151 if (ret < 0) { 152 _debug("bind failed %d", ret); 153 goto error; 154 } 155 } 156 157 switch (local->srx.transport.family) { 158 case AF_INET6: 159 /* we want to receive ICMPv6 errors */ 160 ip6_sock_set_recverr(local->socket->sk); 161 162 /* Fall through and set IPv4 options too otherwise we don't get 163 * errors from IPv4 packets sent through the IPv6 socket. 164 */ 165 /* Fall through */ 166 case AF_INET: 167 /* we want to receive ICMP errors */ 168 ip_sock_set_recverr(local->socket->sk); 169 170 /* we want to set the don't fragment bit */ 171 ip_sock_set_mtu_discover(local->socket->sk, IP_PMTUDISC_DO); 172 173 /* We want receive timestamps. */ 174 sock_enable_timestamps(local->socket->sk); 175 break; 176 177 default: 178 BUG(); 179 } 180 181 _leave(" = 0"); 182 return 0; 183 184 error: 185 kernel_sock_shutdown(local->socket, SHUT_RDWR); 186 local->socket->sk->sk_user_data = NULL; 187 sock_release(local->socket); 188 local->socket = NULL; 189 190 _leave(" = %d", ret); 191 return ret; 192 } 193 194 /* 195 * Look up or create a new local endpoint using the specified local address. 196 */ 197 struct rxrpc_local *rxrpc_lookup_local(struct net *net, 198 const struct sockaddr_rxrpc *srx) 199 { 200 struct rxrpc_local *local; 201 struct rxrpc_net *rxnet = rxrpc_net(net); 202 struct list_head *cursor; 203 const char *age; 204 long diff; 205 int ret; 206 207 _enter("{%d,%d,%pISp}", 208 srx->transport_type, srx->transport.family, &srx->transport); 209 210 mutex_lock(&rxnet->local_mutex); 211 212 for (cursor = rxnet->local_endpoints.next; 213 cursor != &rxnet->local_endpoints; 214 cursor = cursor->next) { 215 local = list_entry(cursor, struct rxrpc_local, link); 216 217 diff = rxrpc_local_cmp_key(local, srx); 218 if (diff < 0) 219 continue; 220 if (diff > 0) 221 break; 222 223 /* Services aren't allowed to share transport sockets, so 224 * reject that here. It is possible that the object is dying - 225 * but it may also still have the local transport address that 226 * we want bound. 227 */ 228 if (srx->srx_service) { 229 local = NULL; 230 goto addr_in_use; 231 } 232 233 /* Found a match. We replace a dying object. Attempting to 234 * bind the transport socket may still fail if we're attempting 235 * to use a local address that the dying object is still using. 236 */ 237 if (!rxrpc_use_local(local)) 238 break; 239 240 age = "old"; 241 goto found; 242 } 243 244 local = rxrpc_alloc_local(rxnet, srx); 245 if (!local) 246 goto nomem; 247 248 ret = rxrpc_open_socket(local, net); 249 if (ret < 0) 250 goto sock_error; 251 252 if (cursor != &rxnet->local_endpoints) 253 list_replace_init(cursor, &local->link); 254 else 255 list_add_tail(&local->link, cursor); 256 age = "new"; 257 258 found: 259 mutex_unlock(&rxnet->local_mutex); 260 261 _net("LOCAL %s %d {%pISp}", 262 age, local->debug_id, &local->srx.transport); 263 264 _leave(" = %p", local); 265 return local; 266 267 nomem: 268 ret = -ENOMEM; 269 sock_error: 270 mutex_unlock(&rxnet->local_mutex); 271 if (local) 272 call_rcu(&local->rcu, rxrpc_local_rcu); 273 _leave(" = %d", ret); 274 return ERR_PTR(ret); 275 276 addr_in_use: 277 mutex_unlock(&rxnet->local_mutex); 278 _leave(" = -EADDRINUSE"); 279 return ERR_PTR(-EADDRINUSE); 280 } 281 282 /* 283 * Get a ref on a local endpoint. 284 */ 285 struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) 286 { 287 const void *here = __builtin_return_address(0); 288 int n; 289 290 n = atomic_inc_return(&local->usage); 291 trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here); 292 return local; 293 } 294 295 /* 296 * Get a ref on a local endpoint unless its usage has already reached 0. 297 */ 298 struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) 299 { 300 const void *here = __builtin_return_address(0); 301 302 if (local) { 303 int n = atomic_fetch_add_unless(&local->usage, 1, 0); 304 if (n > 0) 305 trace_rxrpc_local(local->debug_id, rxrpc_local_got, 306 n + 1, here); 307 else 308 local = NULL; 309 } 310 return local; 311 } 312 313 /* 314 * Queue a local endpoint and pass the caller's reference to the work item. 315 */ 316 void rxrpc_queue_local(struct rxrpc_local *local) 317 { 318 const void *here = __builtin_return_address(0); 319 unsigned int debug_id = local->debug_id; 320 int n = atomic_read(&local->usage); 321 322 if (rxrpc_queue_work(&local->processor)) 323 trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here); 324 else 325 rxrpc_put_local(local); 326 } 327 328 /* 329 * Drop a ref on a local endpoint. 330 */ 331 void rxrpc_put_local(struct rxrpc_local *local) 332 { 333 const void *here = __builtin_return_address(0); 334 unsigned int debug_id; 335 int n; 336 337 if (local) { 338 debug_id = local->debug_id; 339 340 n = atomic_dec_return(&local->usage); 341 trace_rxrpc_local(debug_id, rxrpc_local_put, n, here); 342 343 if (n == 0) 344 call_rcu(&local->rcu, rxrpc_local_rcu); 345 } 346 } 347 348 /* 349 * Start using a local endpoint. 350 */ 351 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) 352 { 353 local = rxrpc_get_local_maybe(local); 354 if (!local) 355 return NULL; 356 357 if (!__rxrpc_use_local(local)) { 358 rxrpc_put_local(local); 359 return NULL; 360 } 361 362 return local; 363 } 364 365 /* 366 * Cease using a local endpoint. Once the number of active users reaches 0, we 367 * start the closure of the transport in the work processor. 368 */ 369 void rxrpc_unuse_local(struct rxrpc_local *local) 370 { 371 if (local) { 372 if (__rxrpc_unuse_local(local)) { 373 rxrpc_get_local(local); 374 rxrpc_queue_local(local); 375 } 376 } 377 } 378 379 /* 380 * Destroy a local endpoint's socket and then hand the record to RCU to dispose 381 * of. 382 * 383 * Closing the socket cannot be done from bottom half context or RCU callback 384 * context because it might sleep. 385 */ 386 static void rxrpc_local_destroyer(struct rxrpc_local *local) 387 { 388 struct socket *socket = local->socket; 389 struct rxrpc_net *rxnet = local->rxnet; 390 391 _enter("%d", local->debug_id); 392 393 local->dead = true; 394 395 mutex_lock(&rxnet->local_mutex); 396 list_del_init(&local->link); 397 mutex_unlock(&rxnet->local_mutex); 398 399 rxrpc_clean_up_local_conns(local); 400 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); 401 ASSERT(!local->service); 402 403 if (socket) { 404 local->socket = NULL; 405 kernel_sock_shutdown(socket, SHUT_RDWR); 406 socket->sk->sk_user_data = NULL; 407 sock_release(socket); 408 } 409 410 /* At this point, there should be no more packets coming in to the 411 * local endpoint. 412 */ 413 rxrpc_purge_queue(&local->reject_queue); 414 rxrpc_purge_queue(&local->event_queue); 415 } 416 417 /* 418 * Process events on an endpoint. The work item carries a ref which 419 * we must release. 420 */ 421 static void rxrpc_local_processor(struct work_struct *work) 422 { 423 struct rxrpc_local *local = 424 container_of(work, struct rxrpc_local, processor); 425 bool again; 426 427 trace_rxrpc_local(local->debug_id, rxrpc_local_processing, 428 atomic_read(&local->usage), NULL); 429 430 do { 431 again = false; 432 if (!__rxrpc_use_local(local)) { 433 rxrpc_local_destroyer(local); 434 break; 435 } 436 437 if (!skb_queue_empty(&local->reject_queue)) { 438 rxrpc_reject_packets(local); 439 again = true; 440 } 441 442 if (!skb_queue_empty(&local->event_queue)) { 443 rxrpc_process_local_events(local); 444 again = true; 445 } 446 447 __rxrpc_unuse_local(local); 448 } while (again); 449 450 rxrpc_put_local(local); 451 } 452 453 /* 454 * Destroy a local endpoint after the RCU grace period expires. 455 */ 456 static void rxrpc_local_rcu(struct rcu_head *rcu) 457 { 458 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); 459 460 _enter("%d", local->debug_id); 461 462 ASSERT(!work_pending(&local->processor)); 463 464 _net("DESTROY LOCAL %d", local->debug_id); 465 kfree(local); 466 _leave(""); 467 } 468 469 /* 470 * Verify the local endpoint list is empty by this point. 471 */ 472 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) 473 { 474 struct rxrpc_local *local; 475 476 _enter(""); 477 478 flush_workqueue(rxrpc_workqueue); 479 480 if (!list_empty(&rxnet->local_endpoints)) { 481 mutex_lock(&rxnet->local_mutex); 482 list_for_each_entry(local, &rxnet->local_endpoints, link) { 483 pr_err("AF_RXRPC: Leaked local %p {%d}\n", 484 local, atomic_read(&local->usage)); 485 } 486 mutex_unlock(&rxnet->local_mutex); 487 BUG(); 488 } 489 } 490